There are many types of different integrated circuit (IC) packages that cater to different applications. Some of the more common IC packages include flip chip and wire-bond ball grid array (BGA) packages. IC packages like BGA packages typically include an IC chip and other components, such as on-package de-coupling (OPD) capacitors placed on a substrate. Generally speaking, IC packages may also include a heat spreader or a lid.
A two-piece lid is usually employed in a typical BGA package. The two-piece lid is formed by attaching a stiffener to sides of the top surface of the package substrate and attaching a heat spreader to the stiffener. Usually, the lid is affixed to the perimeter of the package substrate, taking up valuable space that can otherwise be used for the placement of various components. In other words, a substantial area, or at least the perimeter area, on the surface of the package substrate has to be reserved for the stiffener in the two-piece lid.
Occasionally, a channel lid is used in place of a two-piece lid. Using a channel lid frees up some space on the package substrate. However, the channel lid does not completely free up the space on the perimeter of the package substrate as at least two sides of the perimeter of the package substrate still needs to be reserved for the “legs” of the channel lid. Furthermore, the channel lid, compared to the two-piece lid, has limited holding strength and increases the warpage of the package.
Because of these limitations, a larger package substrate would generally be required for a larger IC since more passive components, e.g., chip capacitors, are required in a device. However, simply enlarging the package substrate is neither a viable nor a cost-effective solution because using a larger package substrate increases manufacturing risks and packaging cost.
Therefore, it is desirable to have accurate a package substrate that can accommodate different types of heat spreaders or lids that take up substantially less area on the package substrate. It is also desirable to have an IC package that can accommodate all the different components without further expanding the size of the package substrate.
It is within this context that the invention arises.